The present invention relates to railway vehicles and more particularly to an arrangement for providing a slackless connection between adjacent ends of railway vehicle units.
Railway vehicle drawbar arrangements of the type to which the present invention relates are normally used in unit train operation wherein a single commodity such as coal, grain or the like is transported from the point of origin to its destination without requiring uncoupling. In such unit trains the usual separable and interlocking couplers may be dispensed with because it is not required to assemble the cars in classification yards or the like.
It has been proposed to replace such separable couplers with a single drawbar extending between adjacent vehicle units and semi-permanently attaching each of the ends as by keying or pinning to the vehicles. Such arrangements while satisfactory have generally introduced the element of slack into the trainline operation as a result of the required loose fit between the key and keyslot to permit horizontal and vertical angling of the drawbar relative to vehicles during normal trainline operation.
In some applications of unit train operation it may be desirable that one end of the drawbar be fully rotatably attached to one of the vehicle units and the other fixed against rotation so as to permit 360.degree. turning of the vehicle to dump the load while the other vehicle or unit remains stationary. Heretofore such rotary arrangements have been incorporated in separable or articulated coupler arrangements.
The prior art drawbar arrangements, because of the rigidity and length of the bar extending between the vehicle units, oftentimes generate stability problems during normal train operation as during the negotiation of curves. It has been discovered that a decrease of the distance between the pivot point about which the vehicle pivots relative to the drawbar and the axis of the center plate immediately inboard of the end to which the pulling drawbar is connected results in decreasing the critical lateral force acting on the truck center pin tending to derail the car.